1. Field of Invention
The present invention relates to an assembly for restraining emitting electrodes in an electrostatic precipitator, and more particularly to such an assembly within an electrostatic precipitator of the type having collecting electrodes arranged in rows spaced at equal distances in parallel planes and spaced-apart emitting electrodes hung in rows centrally between adjacent collecting electrodes.
2. Description of the Prior Art
In the art of electrostatic precipitation it is conventional to provide a housing for the collecting and emitting electrodes, the walls of which housing are constructed of conductive metallic material and grounded. The housing defines an inlet for admitting a particulate-carrying gas and an outlet for discharging such gas reduced in particulate concentration. The precipitator further includes means for providing an electrical potential between the emitting electrodes and the collecting electrodes to create electrical field forces such that particulates in the gas are moved as a result to the collecting electrodes.
In more detail, by groups the emitting electrodes are commonly suspended from an upper supporting frame which is mounted in an insulated manner to the housing. The lower ends of the emitting electrodes are loaded by tensioning weights and retained parallel to and at uniform distances from one another by means of conductive restraining assemblies including a spacing grid supported by and in contact with the electrodes adjacent their lower ends. A number of separating grids are employed in the housing. Each grid typically spans the width of the precipitator and normally has a depth in the direction of gas flow equal to two or more emitting electrodes.
In addition to the above restraining function, the grids prevent the tensioning weights from falling should an emitting electrode break. Further, the grids are commonly constructed of conductive material so that the electrodes in each respective group of retained emitting electrodes are at the same potential.
When the grids are conductive, the restraining assemblies include means to restrict movement of each grid within the precipitator housing and to insulate the grid from the walls of the precipitator housing. As such means, assemblies have included positioning rods constructed of non-conductive material, for example, ceramic and mounted to extend horizontally from the grid toward the walls of the precipitator housing. This approach has not proved entirely satisfactory because during operation of the precipitator, a surface accumulation of dust and grime forms on the rods and at some point the accumulation becomes sufficient to serve as an electrical path by which the grid is shorted to the precipitator wall. Such shorting necessitates costly shutdowns of the precipitation for removal of the accumulation before the emitting electrodes associated with the grid can be put into full service again.